IE8/IE7 Compatibility

forEach.js

    // Production steps of ECMA-262, Edition 5, 15.4.4.18  
    // Reference: http://es5.github.com/#x15.4.4.18  
    if ( !Array.prototype.forEach ) {  
      
      Array.prototype.forEach = function( callback, thisArg ) {  
      
        var T, k;  
      
        if ( this === null ) {  
          throw new TypeError( " this is null or not defined" );  
        }  
      
        // 1. Let O be the result of calling ToObject passing the |this| value as the argument.  
        var O = Object(this);  
      
        // 2. Let lenValue be the result of calling the Get internal method of O with the argument "length".  
        // 3. Let len be ToUint32(lenValue).  
        var len = O.length >>> 0; // Hack to convert O.length to a UInt32  
      
        // 4. If IsCallable(callback) is false, throw a TypeError exception.  
        // See: http://es5.github.com/#x9.11  
        if ( {}.toString.call(callback) != "[object Function]" ) {  
          throw new TypeError( callback + " is not a function" );  
        }  
      
        // 5. If thisArg was supplied, let T be thisArg; else let T be undefined.  
        if ( thisArg ) {  
          T = thisArg;  
        }  
      
        // 6. Let k be 0  
        k = 0;  
      
        // 7. Repeat, while k < len  
        while( k < len ) {  
      
          var kValue;  
      
          // a. Let Pk be ToString(k).  
          //   This is implicit for LHS operands of the in operator  
          // b. Let kPresent be the result of calling the HasProperty internal method of O with argument Pk.  
          //   This step can be combined with c  
          // c. If kPresent is true, then  
          if ( k in O ) {  
      
            // i. Let kValue be the result of calling the Get internal method of O with argument Pk.  
            kValue = O[ k ];  
      
            // ii. Call the Call internal method of callback with T as the this value and  
            // argument list containing kValue, k, and O.  
            callback.call( T, kValue, k, O );  
          }  
          // d. Increase k by 1.  
          k++;  
        }  
        // 8. return undefined  
      };  
    }  
      

map.js

// Production steps of ECMA-262, Edition 5, 15.4.4.19
// Reference: http://es5.github.com/#x15.4.4.19
if (!Array.prototype.map) {
  Array.prototype.map = function(callback, thisArg) {
 
    var T, A, k;
 
    if (this === null) {
      throw new TypeError(" this is null or not defined");
    }
 
    // 1. Let O be the result of calling ToObject passing the |this| value as the argument.
    var O = Object(this);
 
    // 2. Let lenValue be the result of calling the Get internal method of O with the argument "length".
    // 3. Let len be ToUint32(lenValue).
    var len = O.length >>> 0;
 
    // 4. If IsCallable(callback) is false, throw a TypeError exception.
    // See: http://es5.github.com/#x9.11
    if ({}.toString.call(callback) != "[object Function]") {
      throw new TypeError(callback + " is not a function");
    }
 
    // 5. If thisArg was supplied, let T be thisArg; else let T be undefined.
    if (thisArg) {
      T = thisArg;
    }
 
    // 6. Let A be a new array created as if by the expression new Array(len) where Array is
    // the standard built-in constructor with that name and len is the value of len.
    A = new Array(len);
 
    // 7. Let k be 0
    k = 0;
 
    // 8. Repeat, while k < len
    while(k < len) {
 
      var kValue, mappedValue;
 
      // a. Let Pk be ToString(k).
      //   This is implicit for LHS operands of the in operator
      // b. Let kPresent be the result of calling the HasProperty internal method of O with argument Pk.
      //   This step can be combined with c
      // c. If kPresent is true, then
      if (k in O) {
 
        // i. Let kValue be the result of calling the Get internal method of O with argument Pk.
        kValue = O[ k ];
 
        // ii. Let mappedValue be the result of calling the Call internal method of callback
        // with T as the this value and argument list containing kValue, k, and O.
        mappedValue = callback.call(T, kValue, k, O);
 
        // iii. Call the DefineOwnProperty internal method of A with arguments
        // Pk, Property Descriptor {Value: mappedValue, : true, Enumerable: true, Configurable: true},
        // and false.
 
        // In browsers that support Object.defineProperty, use the following:
        // Object.defineProperty(A, Pk, { value: mappedValue, writable: true, enumerable: true, configurable: true });
 
        // For best browser support, use the following:
        A[ k ] = mappedValue;
      }
      // d. Increase k by 1.
      k++;
    }
 
    // 9. return A
    return A;
  };      
}